The equivalent series resistance of a capacitor is the inherent characteristic of a capacitor to have a certain amount of resistance in series with its capacitance characteristics. An ideal capacitor would have no series or parallel resistance, and its impedance would be totally capacitive in nature. However, practical capacitors have both series resistance and parallel resistance, the parallel resistance resulting in leakage of the charge across the capacitor and the series resistance resulting in a reduction in the charging and discharging rates of the capacitor.
The series resistance of a capacitor will vary as the capacitor ages for various reasons including dehydration of the electrolyte. Also, the welds or joints that connect the leads to the capacitor frequently become broken, loose or corroded. It is apparent that if the series resistance of the capacitor becomes large enough the capacitor becomes in essence an open circuit.
Accordingly, when servicing electronic equipment it is desirable for the service technician to measure the equivalent series resistance of the capacitors in the circuit which is under consideration. In the past such tests have been relatively time consuming, and therefore, an object of the present invention is to provide a faster and more economical way to measure the equivalent series resistance of a capacitor.